Javascript: Validate a field: Not empty & only contains numbers [duplicate]

Question

Possible Duplicate:
Validate numbers in JavaScript - IsNumeric()

Hi I am trying to validate a field using javascript to ensure that the field is not empty AND only contains numbers

I am using document.getElementById to get the value of the field, then using this function to validate it:

function isNumeric(elem, message, messsage2)
{
   if(isNaN(elem))
   { 
    alert(message2); 
    return false; 
   }
   else if (elem == null || elem =="")
   {
    alert(message);
    return false;
   }
return true;
}

However this function still allows me to enter letters as where there should be numbers

do you think you are the first person trying to validate number with javascript in 2012? :) see this or this — Michal Klouda
– Michal Klouda, Commented Oct 6, 2012 at 18:45
both those posts are validating numbers, i need a function that validates not empty and only numbers. — Neil
– Neil, Commented Oct 6, 2012 at 18:57

Peter Olson · Accepted Answer · 2012-10-06 18:43:41Z

1

function isNonEmptyNumber (str) {
  if(!str.length) return false;
  var num = +str;
  return isFinite(num) && !isNaN(num);
}

answered Oct 6, 2012 at 18:43

Peter Olson

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Comments

Chocimier · Accepted Answer · 2012-10-06 18:47:19Z

0

With regexp:

value.match(/^\d+$/)

answered Oct 6, 2012 at 18:47

Chocimier

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2 Comments

NullUserException Over a year ago

This will fail to match numbers like 1.2, -1, etc.

NullUserException Over a year ago

Yes, but then you'd get false positives like +++++ or .

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